Constructing Asymmetric Dual Active Sites Through Bimetallic Synergy for Achieving Selective Photocatalytic Nonoxidative Coupling of Methane toward Ethylene
Huimin Li, Qianqian Shen, Zhe Sun, Wenjie Wang, Jinbo Xue, Jiaguo Yu
Abstract
Photocatalytic nonoxidation coupling of methane reactions can directly convert methane into high-value C 2 products under mild conditions. However, the efficient conversion of CH 4 to C 2 H 4 is severely limited by the high C–H bond energy of CH 4 and the slow kinetic process of C–C coupling. Herein, Mo-WO 3– x catalysts with dual active sites were constructed by the isomorphic substitution of Mo 6+ for W in WO 3 . Among them, Mo doping not only induces the preferential formation of oxygen vacancies between Mo and W atoms, but also enhances the catalytic activity of frustrated Lewis pairs composed of unsaturated W and lattice oxygen. The results show that the asymmetric dual active sites of unsaturated Mo and FLPs accelerate the cleavage of CH 4 molecules, reduce the coupling energy barrier of CH 2 intermediates, and synergistically promote the desorption of C 2 H 4 . The catalyst presents a C 2 H 4 yield of up to 152.19 μmol g –1 h –1 with a selectivity of 95%. This work provides insights into the preparation of highly efficient NOCM photocatalysts with a bimetallic synergistic effect.